I've owned my car for the past two years, never having any problems at all. But for the past couple of summers (once it gets hot usually) I get an annoying rattle from the engine.

The problem is very consistant and can be replicated nearly every time once the car is warmed up. When I am driving or accelerating in any gear, then press the clutch to coast. The rpms dip below idle (around 500rpm) making the engine rattle for around a second then jump back to normal idle rpm without problems.

I dont notice this problem in the winter or when the engine is cold. Ive had this issue for 2 years, and the oil analysis was great. So I know its not harming anything, its just rather annoying. Ive cleaned and replaced the MAP sensor with no improvement, anyone else have an idea on what it could be?

 

My first question is why are you pressing in the clutch pedal to coast?

 

Check or replace the idle air control valve. It's that rectangular piece bolted to the side of the intake manifold.

Also check or replace the manifold absolute pressure sensor. The narrow passage leading to the sensor may be clogged.

 

Kinda a shot in the dark, but does it only rattle when the engine dips to an RPM that would create a lot of vibration? If so mabye it could be your clutch fork rattling??

 

I dont because it doesnt make sense to just coast in neutral. I was just trying to paint a picture to describe how its replicated. I should have worded it differently.

 

I would say its definantly the engine dipping to low in the rpm range thats causing it. I can rev the car in neutral without the clutch and it still happens when the rpms come down.


Thanks, ill be checking this next!